1. Field of Invention
Embodiments of the invention relate generally to inflatable devices. More specifically, at least one embodiment relates to an apparatus and method for monitoring and controlling the pressure in an inflatable device, for example, based on a user selected inflation level.
2. Discussion of Related Art
Inflatable devices are used in a variety of contexts, such as where buoyancy or a cushioned support is needed, where space is limited or portability is desired. For example, inflatable mattresses, cushions and other body supports (e.g., pillows, backrests, chairs, etc.) are used for applications such as camping, hospital bedding, and both occasional and everyday bedding and support in the home. Many inflatable devices can be inflated to a desired pressure level using an inflation device such as an electrically operated pump. Generally, these inflatable devices also include at least one valve (either manually operated or electrically operated) that allows control of the pressure in the inflatable valve, for example, by allowing the release of fluid from the inflatable device when the valve is open. Such inflatable devices have the additional advantage that the degree of inflation of the inflatable device can be adjusted to provide selective support for objects having an irregular shape, such as a person. Other examples of inflatable devices include boats, rafts and other devices for use in the water.
A variety of methods are known for providing a fluid, such as air, to inflate an inflatable device. Typically, a pump is used to supply fluid to an orifice in the inflatable device. In most instances, fluid is introduced into inflatable devices through an inlet that may be sealed to retain fluid within the inflatable device. The inlet may also serve as an outlet for deflating the inflatable device. A pump for use with an inflatable device may include a motor that drives an impeller, moving the fluid into, out of (or both), the inflatable device. Motorized pumps may be powered by electricity. Typically, such electricity is provided by a connection to standard house current or, where portability is desired, batteries.
One known inflatable device invented by the applicant is disclosed in U.S. Pat. No. 5,267,363, which is herein incorporated by reference. The inflatable device includes a bladder 20, which is adapted for use as a mattress. The inflatable device also includes a fluid controller 80 connected to bladder 20 comprising a pump adapted to inflate the bladder 20 when connected to household electric current.
Some inflatable devices include a pressure control system that allows a user to select the pressure level in the inflatable device based on a number that appears to correspond with a discrete pressure level. That is, the system may provide the user with multiple pressure settings where one or more of the pressure settings corresponds to an associated number or other indicia identifying that pressure setting. Further, once the pressure setting is selected, the pressure control system adjusts the pressure in the inflatable device by either operating the inflation device (i.e., to increase the pressure by adding fluid to the inflatable device) or opening the valve (i.e., to decrease the pressure by allowing fluid to be released from the inflatable device).
However, these known pressure control systems require that the user recall their preferred setting whenever they use the inflatable device after the pressure level in the inflatable device has been changed, for example, as the result of the use of the inflatable device by another user, gradual leakage, deflation for storage, etc. Provided the user recalls their preferred setting, the user must then adjust the pressure control setting to select the setting associated with the pressure that they prefer from among, perhaps, many pressure settings. Further, the association of the pressure of the inflatable device and the pressure setting of the pressure control is arbitrary. As one example, the controls may provide unequal steps of pressure adjustment between each control setting. More specifically, where the pressure control system provides the user with 20 different pressure control settings (e.g., identified by the numerals 1-20) the change in pressure between adjacent settings (e.g., the settings 5 and 6) may differ between each step of adjustment. In addition, the user cannot be sure that there is any difference between the pressure provided by a first pressure control setting and a pressure provided by a second pressure control setting, e.g., the pressure provided when the system is set at the pressure control setting ‘5’ may be exactly the same as, or differ little from, the pressure provided when the system is set at the pressure control setting ‘6.’
Also, existing pressure control systems may not provide fast enough adjustment, in particular, where the inflatable device has a relatively large volume (e.g., a mattress). The lack of relatively rapid adjustment makes current pressure control systems impractical for use in inflatable devices that provide posture control.